1. Field of the Invention
The present invention relates generally to semiconductor integrated circuit manufacturing and, more particularly to a method of forming a silicon-containing dielectric film on a semiconductor substrate by cyclic deposition such as atomic layer deposition and cyclic chemical vapor deposition with side wall coverage control.
2. Description of the Related Art
As methods of depositing dielectric films on substrates, typically chemical vapor deposition (CVD) and atomic layer deposition (ALD) are known. A skilled artisan often uses plasma-enhanced CVD (PE-CVD) and plasma-enhanced ALD (PE-ALD) to form dielectric films. PE-ALD is a deposition technology of dielectric films using chemisorption of precursors and can improve a step coverage of films depositing on recess patterns of substrates, as compared with PE-CVD. However, when depositing a dielectric film other than SiO film by PE-ALD on a recess pattern, where nitration or carbon substitution reaction is conducted in an atmosphere with plasma, the thickness of film deposited on a sidewall is sometimes small relative to the thickness of film deposited on a top surface. This problem may be caused by ion collision interfering with reaction speed on the sidewall as compared with that on a top or bottom surface. Particularly, nitration has a low rate of sidewall reaction as compared with oxidation, causing problems of thin film deposited on a sidewall, deterioration of film deposited on a sidewall, etc. Since reactivity of a precursor with a reactant gas affects step coverage and thickness of depositing film, the present inventors have conducted research to improve reactivity inside a recess in not only PE-ALD but also other cyclic deposition methods.
Any discussion of problems and solutions involved in the related art has been included in this disclosure solely for the purposes of providing a context for some, not all, embodiments of the present invention, and it should not be taken as an admission that any or all of the discussion were known at the time the invention was made.